Patients with the Borderline Personality Disorder and the Dependent Personality Disorder both suffer from abandonment and separation anxieties and are clinging, demanding, and emotionally labile - but their sexual behavior is distinguishable. The borderline uses her sexuality to reward or punish her mate. The dependent uses it to "enslave" and condition her lover or spouse. The borderline withholds sex or offers it in accordance with the ups and downs of her tumultuous and vicissitudinal relationships. The codependent tries to make her mate addicted to her particular brand of sexuality: submissive, faintly masochistic, and experimental.
(From the book "Malignant Self-love: Narcissism Revisited" by Sam Vaknin - Click on this link to purchase the print book, or 16 e-books, or 3 DVDs with 16 hours of video lectures on narcissists, psychopaths, and abuse in relationships: http://www.narcissistic-abuse.com/thebook.html)